1. Field of the Invention
The invention generally relates to a vibratory compactor used, e.g., to compact asphalt or soil, and more particularly, relates to a ride-on vibratory compactor of the above-mentioned type having a multi-function control lever.
2. Discussion of the Related Art
Vibratory compactors are used in a variety of soil and asphalt compaction and leveling applications. Most vibratory compactors have plates or rollers that rest on the surface to be compacted that are excited to vibrate so as to compact and level the worked surface. A common vibratory compactor, and one to which the invention is well-suited, is a so-called “double drum roller” used to compact asphalt or soil.
The double drum roller includes a chassis supported on the surface to be compacted by two (front and rear) rotating drum assemblies, each of which may support a respective subframe of the chassis. Each of the drum assemblies is driven to rotate by a dedicated hydraulic motor. Both hydraulic motors are supplied with pressurized hydraulic fluid from a pump powered by an internal combustion engine mounted on one of the subframes. In addition, each drum assembly is excited to vibrate by a dedicated exciter assembly that is located within the associated drum assembly and is powered by a hydraulic motor connected to a pump. Each exciter assembly typically comprises one or more eccentric masses mounted on a rotatable shaft that is positioned within the drum assembly. Rotation of the eccentric shaft imparts vibrations to the remainder of the drum assembly.
An operator support platform is typically situated on the subframe of the chassis and provides an operator's seat for supporting the operator of the roller. A control assembly for operating travel and operations of the roller is typically located near the operator and may include a steering wheel for controlling directional steering and a control lever for controlling forward and rearward travel by selective movement of the control lever in the forward and rearward directions, respectively. The control lever is typically cable-operated and has a relatively long stroke length between its forward-most and rearward-most positions. During operation, the operator of the roller typically maintains one hand on the steering wheel for steering and the other hand on the control lever to control forward and backward travel.
The control assembly further includes a number of control elements, e.g., buttons, switches, knobs, and the like located on the dash of the roller and configured to be selected for carrying out a multitude of functions of the roller. For instance, the control elements are provided to control the activation and deactivation of the vibratory exciter assemblies, switching between which of the vibratory exciter assemblies is active, controlling the level of vibration, e.g., high and low, operating a spray assembly configured to spray the drum with water, and sounding a horn element to alert individuals to the presence of the roller.
Ride-on rollers are typically used in a cyclical manner, i.e. driving back and forth over a section of soil or asphalt to compact the surface. The cyclical operation of the machine requires a high duty cycle on the control lever. Further, it is often desired to switch between the front and rear vibratory exciters when switching between the forward and rearward movement and vice versa to maximize vibration in the lead drum assembly, i.e., the front drum assembly in the forward direction and rear drum assembly in the rearward direction. The high duty cycle with respect to forward and backward travel and actuation of the lead vibratory exciter results in the operator of the roller repeatedly switching between a forward-facing position for forward travel and rearward-facing position for rearward travel.
The high duty cycle of the control lever for forward and rearward movement and for switching between the lead vibratory exciters hinders roller control because the operator must remove his or her hand from the control lever or steering wheel to actuate the control elements located on the dash. Thus, the operator must repeatedly move his or her hand between the control lever or steering wheel and the controls on the dash, which limits the operator's ability to control movement of the roller. Moreover, when moving in reverse, this process is made even more difficult because the operator must blindly remove his or her hand from the control lever or steering wheel, search for the appropriate control element on the dash, and return his or her hand to the control lever or steering wheel while the roller is in motion. In the alternative, the operator may take his or her eyes off the direction of travel to find the appropriate control element, which is understandably inherently dangerous to the operator as well as others in the area.
While some known ride-on vibratory rollers include a control element on the control lever for turning the exciter assemblies on and off, the rest of the control elements are located on the dash. The operator of such a ride-on vibratory roller still must remove his or her hand from the control lever and/or steering wheel repeatedly to control the various other functions of the roller and most notably to switch between which of the exciter assemblies is activated to correspond to a direction of travel so the lead exciter assembly's vibratory impact on the work surface is maximized.
The need therefore exists to provide a control assembly and control method for a vibratory ride-on roller of the like that eliminates one or more of the foregoing disadvantages.